In general, motorised racking systems have been known for some time, capable of storing goods dynamically.
These racking systems are capable of setting the stored goods in motion until they present a sought object at a picking station from which it can be taken.
In general, the techniques of moving the goods most widely used are those in which the goods are arranged inside containers or boxes which are made to circulate freely by means of, and on, conveyor devices.
In the case of storage on conveyor devices, it is desirable to use systems for dynamic identification of the moving objects, for example of the type using barcodes, magnetic code, transponders or similar, which is not however required for fixed racks where it is sufficient to store in a database the location where the item has been placed.
Currently, motorised racking systems are known of the type with a single track, which are capable of carrying out a service analogous to racking systems of the gravity type, i.e. capable normally of housing only a single type of article or goods in movement.
In this case the picking sequence is a predefined sequence to define a system of warehousing usually identified by the acronym LIFO (last in, first out: the last to come in is the first to go out) if access is from a single side; or on the other hand with the acronym FIFO (first in, first out): the item which came in first is the first to go out) if the loading of the boxed goods takes place on one side while unloading takes place on a different side.
Racking systems of these types are for example described and illustrated in the International Patent application PCT no. WO 02/074663 and in United States patent application no. US 2003/152446.
Motorised racks of the recirculating type are also known, including a system of conveying in a loop in which the stored goods can move in a closed circuit or loop and therefore present themselves selectively at a pre-established station, from which it is then possible to carry out the loading of new boxed goods or the unloading outwards of goods previously warehoused in the said racks.
These types of recirculating racks in general include parallel linear conveyors provided with 180° curves at the ends, and are characterised by a constant high-speed motion, and therefore allow rapid operations of search and identification of objects, although for the extraction of the objects themselves, complicated devices are necessary which require manipulation techniques; furthermore, the above-mentioned curves necessitate relatively large dimensions and are therefore cumbersome.
Racking systems of these types are for example described and illustrated in Japanese Patent application no. JP 1.122.814 and in U.S. Pat. No. 3,303,918.
Other types of motorised racks currently known are defined by conveyor means arranged side by side, capable of moving the boxed goods in opposite directions. In these racks, there are means of stopping and means of lateral transposition capable of allowing the movement of the boxed goods.
These racks, as for example those described and illustrated in International Patent application no. WO 99/35061, in Japanese patent application no. JP 1.321.205 and in U.S. Pat. No. 3,662,905, have the advantage of being of compact dimensions, with structurally simple exit/entry portions for the goods, but have extremely low productive speeds of recirculating movement because of the continual stops and transposing movements.